Enhanced Projectile for Modern Pneumatic Sporting Devices /Air Rifles

ABSTRACT

A novel enhanced projectile, designed for use with air rifles and sub-sonic applications is disclosed. The enhanced projectile includes an air core that extends the full length of the projectile.

PRIORITY CLAIM AND CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit under 35 U.S.C. § 119(e)(1) of U.S. Provisional Application No. 63/121,635, filed Dec. 4, 2020, which is hereby incorporated by reference in its entirety.

BACKGROUND

An air gun is a type of gun that launches projectiles pneumatically with compressed air or other compressed gases (air is already a mixture of various gases), with the gases at ambient temperatures. Such “non-firearm” guns can come in several varieties, such as pump air guns, CO₂ cartridge air guns, and PCP (Pre-Charged Pneumatics) air guns, which utilize a reservoir or “tank” of compressed air or gases. A PCP air gun may be an unregulated mechanical PCP, a regulated mechanical PCP, or an electronic PCP.

A conventional firearm, by contrast, generates pressurized combustion gases chemically through exothermic oxidation of combustible propellants, such as gunpowder, which generate propulsive energy by breaking molecular bonds in an explosive production of high temperature gases. In modern firearms, the combustion gases are generally formed within a cartridge comprising the projectile inserted into a casing containing the fuel. This propulsive energy is used to launch the projectile from the casing, and thus from the firearm.

Other differences between air guns and conventional firearms can be observed as differences in pressures inside the respective barrels, muzzle energies, projectile speeds, and projectile weights that can be shot, for example. A conventional rifle chambered for a .22 long rifle (LR) cartridge fires a 40-grain bullet at approximately 1200 ft/sec. A powerful air rifle may fire a 14.3 grain pellet with a muzzle velocity of approximately 900 ft/sec. The conventional firearm generates a muzzle energy of approximately 130 ft-lbs of energy at the muzzle whereas that of the air rifle generates only about 26 ft-lbs.

The compressed gas or air of air guns can have maximum pressures of 4500-5000 psi, but these high pressures are not currently in common use. On the other hand, by comparison, the lowest pressure rifle cartridges may be black powder cartridges of yesteryear and certain rimfire cartridges. Some of these lesser firearm cartridges still generate barrel pressures of 15,000-20,000 psi, or 20,000-25,000 psi for rimfire, which is a much higher pressure level than air guns can currently achieve.

Therefore, the conventional high power air rifle is still “handicapped” in comparison to conventional firearms by low operating pressure of ⅕ that of a firearm, or lower, which is its primary limitation when being compared with firearms. This limitation can restrict the type and size of projectile that an air gun can launch, based on the mass of the projectile and the limited available energy of the air gun.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description is set forth with reference to the accompanying figures. The use of the same reference numbers in different figures indicates similar or identical items.

For this discussion, the devices and systems illustrated in the figures are shown as having a multiplicity of components. Various implementations of devices and/or systems, as described herein, may include fewer components and remain within the scope of the disclosure. Alternately, other implementations of devices and/or systems may include additional components, or various combinations of the described components, and remain within the scope of the disclosure. Shapes and/or dimensions shown in the illustrations of the figures are for example, and other shapes and or dimensions may be used and remain within the scope of the disclosure, unless specified otherwise.

FIG. 1A shows a right side view of an example air rifle.

FIG. 1B shows a section view of an example air rifle, showing interior details.

FIG. 2A shows example prior art standard metal-jacketed or solid metallic projectiles in cartridges.

FIG. 2B shows example lightweight projectiles for air rifles.

FIG. 3A shows a top view of an example novel projectile, according to an embodiment.

FIG. 3B shows a perspective view of an example novel projectile, according to an embodiment.

FIG. 4A shows a top view of an example novel projectile, according to another embodiment.

FIG. 4B shows a side cross-sectional view of an example novel projectile, according to another embodiment.

FIG. 5A shows a top view of an example novel projectile, according to another embodiment.

FIG. 5B shows a side cross-sectional view of an example novel projectile, according to another embodiment.

FIG. 6A shows a top view of an example novel projectile, according to another embodiment.

FIG. 6B shows a side cross-sectional view of an example novel projectile, according to another embodiment.

FIG. 7A shows a top view of an example novel projectile, according to another embodiment.

FIG. 7B shows a side cross-sectional view of an example novel projectile, according to another embodiment.

DETAILED DESCRIPTION Overview

A modern pneumatic sporting device or air rifle (hereinafter “MPSD 100”) is a type of gun that launches projectiles pneumatically with compressed air or other compressed gases, with the gases at ambient temperatures, as described above. An example MPSD 100 provides an environment for the application of an enhanced projectile 102.

Referring to FIGS. 1A and 1B, the operation of a typical MPSD 100 is described. The one or more propellant gases of a MPSD 100 go from high pressure to a lower pressure when propelling any projectile, but the one or more gases remain the same gases chemically. Significantly, the current pressure level in the reservoir or gas source of a MPSD 100 before a projectile is shot (which can be upwards of 6000 psi in some cases) represents the maximum pressure that can be achieved behind a projectile in a conventional MPSD 100, because there is no explosive combustion of gunpowder to create additional pressure (no expanding gases). Accordingly, the pressure curve for a conventional MPSD 100 is characterized by diminishing gases and low or no heat, which provides the energy for propelling a projectile from the MPSD 100. The initial lower pressures of MPSDs 100 and the diminishing pressure characteristic cause lower forces, which cause more limited bullet accelerations.

For example, it takes a certain amount of energy to push a projectile into the rifling of a rifle barrel, since the rifling often has an overall diameter that is slightly less than the outer diameter of the projectile. Much of the available energy from the high-pressure gas is used to push the projectile into the rifling, deforming it to fit the rifling, which diminishes the total energy available to generate the desired velocity for the projectile.

When the MPSD 100 is triggered, the hammer strikes the valve stem, opening the valve and quickly releasing some of the pressurized gases from the reservoir into the chamber behind the projectile. Projectile acceleration starts at zero as the compressed gas enters the chamber of the MPSD 100 until there is enough breech pressure for the projectile to move. The pressure within the chamber rises as stored compressed gases are introduced into the chamber. Pressure within the chamber quickly builds to match the gas pressure of the compressed gas reservoir (which may be onboard or remote from the MPSD 100). The valve spring and the pressure within the reservoir combine to quickly reseat the valve, stopping the release of gas from the reservoir.

The projectile is expelled from the barrel of the MPSD 100 if sufficient pressure is present behind the projectile. The pressure of the gases within the chamber and within the barrel behind the projectile diminishes as the projectile travels down the barrel, since the volume the gas occupies increases. As the projectile moves down the length of the barrel, the compressed gas expands to fill the additional volume inside the barrel and the void created by the projectile moving down the barrel bore. The available energy to perform the work of driving a projectile diminishes as the gas expands, thus reducing the force on the projectile as it travels down the barrel. With the increase of volume, the gas cools as it loses energy and pressure, finally dropping to ambient pressure as the projectile leaves the end of the barrel.

A portion of the pressurized gas stored in the gas reservoir is released into the firing chamber when the MPSD 100 is triggered. As an amount of the compressed gas passes into the chamber and barrel of the MPSD 100, the volume of gas in the reservoir tank is decreased and the gas pressure also decreases. Accordingly, less pressure and less energy is available for subsequent triggering events. After a number of shots, the gas reservoir no longer has sufficient gas pressure (e.g., stored energy) for additional shots, and is recharged to full pressure prior to any subsequent triggering events.

Referring to FIG. 2A, standard metal-jacket bullets and solid metallic projectiles 202 for firearms are conventionally considered unusable for MPSDs 100, as they are difficult to deform into the rifling, have a high coefficient of friction, and are propelled too slowly for conventional MPSDs 100 to be effective. They are typically propelled from conventional firearms using an explosion of combustibles within the cartridge 204. An MPSD 100 does not use the combustibles or the cartridge 204, and instead uses compressed gas to propel a projectile. The lack of relative power of an MPSD 100 is compensated for by using very soft and lightweight projectiles 206 to get desired projectile velocities. Thus, conventional MPSDs 100 generally use alternative projectiles 206, shown at FIG. 2B. As shown, MPSD projectiles 206 generally consists of very malleable light-weight spherical shot or diablo-shaped pellets (wasp-waist shaped) that are light enough to be launched by the compressed gases of the MPSD 100. For example, .177 pellets for MPSDs 100 weigh approximately 7 grains compared to .172 rifle bullets that weigh from around 18 to 25 grains. In another example, .22 pellets for MPSDs 100 weigh approximately 12 grains compared to 35 to 55 grains for conventional .22 bullets and up to 80 grains for long range (LR) match conventional .22 bullets for firearms.

Diablo-shaped pellets 206 may be considered modified shot. They usually comprise a soft metallic pellet with an attached skirt to reduce blow-by when they are fired and that may that assist with stabilization during flight. Some conventional MPSDs 100 may also shoot BBs, darts, or arrows. Based on the shape of the typical MPSD projectiles 206 and the lower energy of the compressed air, many MPSDs 100 have a limited range and application. For instance, conventional air guns using projectiles 206 such as shot or diablo-shaped pellets or slugs may not be effective for hunting at desired distances.

Standard copper-jacketed or solid metallic projectiles 202 known as hollow points are designed to force the expansion of the nose of the bullet to create a larger wound cavity by expanding the projectile's diameter, using the mass of the target animal to force the projectile 202 to deform and expand. This expansion comes at the expense of the projectile's energy, reducing its ability to cause efficient terminal effectiveness at lower velocities.

EXAMPLE EMBODIMENTS

Representative implementations of devices and techniques disclosed herein describe techniques and devices for overcoming the common deficiencies of a modern air rifle: propelling a projectile from a MPSD 100 at a desired velocity to result in a terminal event, particularly with regard to a large animal in a hunting scenario. The techniques and devices disclosed herein provide a novel enhanced projectile 302, designed for use with air rifles and sub-sonic applications that forms a similar wound cavity in an animal as an expanding projectile 202, without the projectile 302 expanding in the flesh of the animal to form the desired wound cavity. Further, the novel projectile 302 maintains the ability to function as a solid projectile for penetration through skin, hide, bone, or other obstructions.

Unlike a conventional bullet 202, (and in contrast to a conventional hollow point bullet 202) the novel enhanced projectile 302 revealed herein does not require any expansion of the projectile 302 to create a larger wound cavity for an efficient terminal event. In some cases, the central air core 304 of the projectile 302 (described further below) captures or collects tissue from the animal as the projectile 302 penetrates the animal and moves through the tissue of the animal. The captured tissue causes the enhanced projectile 302 to wobble and tumble, which creates a larger wound cavity, as described further below.

Also, unlike a conventional hollow point bullet 202, the hollow central air core 304 of the enhanced projectile 302 does not negatively impact the aerodynamics of flight. In the case of a conventional hollow point bullet 202, the hollow point at the nose traps air in the cavity of the hollow point. The trapped air is compressed within the hollow point and remains trapped until the bullet expands (usually on impact), with the conventional bullet deforming and/or destructing. The trapped air can increase the drag on the bullet 202, decreasing speed and reducing range and accuracy. In contrast, the hollow central air core 304 of the enhanced projectile 302 prevents trapped air and the compression of trapped air at the nose 306. Instead, the air core 304 allows (and in some cases enhances, as described further below) the passage of air through the air core 304, providing improved aerodynamics of the projectile 302. This aerodynamic advantage increases the speed, range, and accuracy of the enhanced projectile 302.

FIG. 3A shows a top view of an example enhanced projectile 302 and FIG. 3B shows a perspective view of the same. FIGS. 4A and 5A also show top views of example enhanced projectiles 302 and FIGS. 4B and 5B shown side cross-sectional views of example enhanced projectiles 302, according to various embodiments. Projectiles 302 illustrated in the figures and discussed herein may be between 22 caliber (.22) to 100 caliber (1.00). However, smaller or larger calibers are also contemplated and are within the scope of this disclosure.

Referring to FIGS. 3A-5B, in various embodiments, the novel projectile 302 has a generally cylindrical body with a tapered nose 306 and a blunt or flat base 308 opposite the nose 306. The projectile 302 includes a hollow core 304 at its primary central axis throughout the length of the projectile 302. The primary central axis runs the length of the projectile 302 and is located at the center of gravity on the lengthwise axis (e.g., longitudinal axis of symmetry of the cylindrical body), such that the projectile 302 spins or “rolls” on the primary central axis when propelled by the MPSD 100.

As shown, a central air core 304 is present along the primary axis, extending from the nose 306 to the base 308 of the projectile 302. The central air core 304 may have a circular cross-section, as shown in the illustrations, or it may have another cross-sectional shape (e.g., polygonal). The projectile 302 is otherwise constructed of a solid metal, such as copper, or other solid natural or synthetic material.

The hollow central air core 304 comprises an orifice, opening, space, hole, etc. that extends from the nose 306 to the base 308. That is, the hollow central air core 304 extends through the entire projectile 302, such that air can pass through the central air core 304 of the projectile 302 as the projectile 302 moves through the air while in flight. In some embodiments, the diameter “d” (or width) of the central air core 304 is constant along the length of the projectile 302, as shown at FIGS. 3A-5B.

The diameter “d” of the central air core 304 may vary depending on the caliber of the projectile 302. For instance, the diameter “d” of the central air core 304 may be a ratio or fraction of the diameter of the projectile 302 (e.g., about 0.25 of the diameter of the projectile 302). However, since the diameter of a particular caliber of projectile 302 can vary, the central core 304 diameter can be a range, such as between 0.2 and 0.4 of the largest diameter of the projectile 302. Accordingly, a few examples can include: a 30 caliber projectile 302 can have a core 304 diameter “d” of between 0.080″ and 0.090″; a 458 caliber projectile 302 can have a core 304 diameter “d” of between 0.187″ and 0.190″; a 50 caliber projectile 302 can have a core 304 diameter “d” of between 0.200″ and 0.212″; a 65 caliber projectile 302 can have a core 304 diameter “d” of between 0.250″ and 0.375″; and a 100 caliber projectile 302 can have a core 304 diameter “d” of between 0.375″ and 0.400. However, in various embodiments, the diameter “d” of the central air core 304 may be smaller or greater and remain within the scope of this disclosure.

In other embodiments, the diameter “d” may change size along at least a portion of the length of the projectile 302, as shown at FIGS. 6A-7B. For example, as shown at FIGS. 6A and 6B, the diameter “d” of the hollow air core 304 may change from a smaller diameter “d” (such as 1 mm, for example) at the nose 306, and enlarge to a greater diameter “d” (such as 2 mm, for example) at the base 308. In an alternative embodiment, the diameter “d” of the hollow air core 304 may change from a smaller diameter “d” (such as 1 mm, for example) at the base 308, and enlarge to a greater diameter “d” (such as 2 mm, for example) at the nose 306. In various implementations, the range of the diameter “d” may be greater or less on one end (306, 308) or either end of the projectile 302. In either case, the substantially “conical” profile of the central air core 304 can have an advantageous effect on the speed, range and accuracy of the flight path of the projectile 302.

Further, as shown at FIGS. 7A and 7B, the diameter “d” of the hollow air core 304 may change from a greater diameter “d” (such as 2 mm, for example) at the nose 306 and the base 308, and reduce to a smaller diameter “d” (such as 1 mm, for example) between the nose 306 and the base 308. In such embodiments, the hollow central air core 304 may have a substantially “venturi” shaped profile. In an example, air moving through the venturi-shaped air core 304 can have a greater velocity than air passing over the outer body of the projectile 302, which can have an advantageous effect on the speed, range and accuracy of the flight path of the projectile 302. Adjusting the position of the neck 702 of the venturi-shaped air core 304 (where the diameter “d” is the smallest) relative to the length of the projectile 302 can adjust the range and accuracy for a particular caliber and/or type or shape of projectile 302. In an alternate embodiment, the diameter “d” at either the nose 306 or the base 308 may be greater than at the other of the nose 306 or the base 308.

For instance, as shown at FIG. 4B, in some embodiments, the projectile 302 may include a relief or depression 310 around the body of the projectile 302. The depression 310 comprises a narrowing of the body of the projectile 302 at an area between the nose 306 and the base 308. The depression 310 can affect the aerodynamics of the projectile 302, and have an advantageous effect on the speed, range and accuracy of the flight path of the projectile 302. In various embodiments, the depth of the depression 310 or narrowing of the body of the projectile 302 may be greater or lesser.

In another example, as shown at FIG. 5B, the base 308 of the projectile 302 may include a taper 502 around the perimeter of the base 308. In various implementations, the taper 502 may have various shapes, such as a boat tail shaped taper, a rounded taper, a sharp taper, and so forth. The taper 502 can affect the aerodynamics of the projectile 302, and have an advantageous effect on the speed, range and accuracy of the flight path of the projectile 302. In various embodiments, the depth and/or angle of the taper 502 at the base 308 of the projectile 302 may be greater or lesser. For instance, the taper 502 may be disposed more or less on the side walls of the projectile 302 or more or less on the base 308 surface of the projectile 302. In alternate embodiments, the base 308 surface can be planar or be slightly rounded, with or without the taper 502.

The presence of the air core 304 can provide improvement in ballistic performance, and particularly at sub-sonic projectile 302 velocities. The air core 304 provides particular enhancements in terminal performance, as described below.

Application

For a desired terminal event, a projectile needs to penetrate an animal to a sufficient depth (e.g., several inches) and to produce a wound cavity approximately twice the diameter of the projectile. As described above, it can be difficult for a solid metal projectile to attain the velocity (e.g., energy) to penetrate properly or to expand when used with pneumatic rifles and other sub-sonic applications. Most pneumatic rifles typically do not have the ability to impart the needed energy to the projectile.

In various implementations, as shown at FIGS. 3A-7B, a hollow core 304 is disposed along the central primary axis of an otherwise solid metal projectile 302. The projectile 302 may be comprised of solid copper or another metal or non-metal. The air core 304 runs the full length of the projectile 302, from the nose 306 to the base 308.

At high velocities (such as velocities approaching the speed of sound, and greater) a pressure wave is formed at the nose 306 of the projectile 302, which can reduce air flowing through the hollow core 304 in some cases. However, at reduced velocities, air can flow through the core 304, reducing a rate of energy loss and velocity loss of the projectile 302, improving speed and range.

In various examples, additional drag-reducing features may also be used on the novel projectile 302. In one example, as shown at 4B, the body of the projectile 302 may include a relief or depression 310, which slightly reduces the diameter at or near the middle of the projectile 302, forming a lower pressure zone. The relief or depression 310 may be disposed around the entire perimeter of the body of the projectile 302, or one or more portions of the perimeter.

The lower pressure zone can reduce drag or air resistance of the projectile 302 as it travels through the air. The relief or depression 310 is shown having a profile comprising a curve that is a portion of a circle or ellipse. However, this is not intended to be limiting, as the relief or depression 310 may have a profile of any shape, including irregular shapes, polygonal shapes, and so forth.

In another example, as shown at FIG. 5B, the end portion of the projectile 302, at the base 308, can be tapered to form a “boat-tail” 502, which also reduces drag or air resistance of the projectile 302 as it travels through the air. The taper 502 is illustrated to have an approximately 45 degree angle with the base 308. In various embodiments, the taper 502 may have a steeper or shallower angle than the example illustrated.

In various embodiments, the middle depression 310 and the boat-tail taper 502 can be employed separately or in combination on a novel projectile 302.

Terminal Event

When the novel projectile 302 impacts an animal, the projectile 302 acts like a solid metal projectile, providing good penetration (of several inches) in heavy skinned animals, even penetrating through bone. During penetration, the core 304 becomes filled with flesh as it moves through the animal. The presence of the flesh in the core 304 upsets the projectile's center of gravity, causing the projectile to wobble or tumble (i.e., yaw and tilt).

The wobble or tumble of the projectile 302 creates a permeate wound cavity slightly larger than the projectile's overall length. The wobbling or tumbling projectile 302 tears away the flesh and bone of the animal far beyond what a standard hollow point expanding bullet can do, since the novel projectile 302 doesn't lose any of its mass or its overall shape as it travels through the animal. This effect functions with little respect to the projectile's original shape. However, the longer the projectile 302, the better it functions (e.g., the more desired wobble or tumble is generated within the animal forming an oversized wound).

The volume and shape of the air core 304, as well as the length of the projectile 302 relative to its diameter can be fine-tuned for specific applications (e.g., for hunting particular animals at desired distance ranges). The use of one or more additional drag-reducing features, as described above, can also be included to form prearranged projectiles 302 for particular applications or ranges of applications.

In actual field tests on deer, the actions and effects described herein have been verified, with projectile velocities as low as 600 feet per second and up to 1000 fps, and penetration through the animals.

Any of the disclosed devices and techniques may be used in any combination with an air rifle or sub-sonic application to provide consistent and reliable projectile performance. Further, it is also acknowledged herein that the enhanced projectile 302 with a central air core 304 as disclosed, and in various embodiments, may be used in high velocity applications, including with conventional and unconventional firearms using combustible materials for propulsion, or using other propulsion techniques. The enhanced projectile 302 with a central air core 304 may be applied in these and other applications by a person having skill in the art. In some applications, the enhanced projectile 302 with a central air core 304 may be used in cartridge form, for instance, with a propellant in a casing.

Although various implementations and examples are discussed herein, further implementations and examples may be possible by combining the features and elements of individual implementations and examples.

The subject matter of the present disclosure is described with specificity to meet statutory requirements. However, the description itself is not intended to limit the scope of this disclosure. Rather, the claimed or disclosed subject matter might also be embodied in other ways to include different components, steps, or combinations thereof similar to the ones described in this document, in conjunction with other present or future technologies. Terms should not be interpreted as implying any particular order among or between various steps disclosed herein unless and except when the order of individual steps is explicitly described.

For purposes of this disclosure, the word “including” has the same broad meaning as the word “comprising.” In addition, words such as “a” and “an,” unless otherwise indicated to the contrary, include the plural as well as the singular. Thus, for example, the constraint of “a feature” is satisfied where one or more features are present. Also, the term “or” includes the conjunctive, the disjunctive, and both (a or b thus includes either a or b, as well as a and b).

CONCLUSION

Although the implementations of the disclosure have been described in language specific to structural features and/or methodological acts, it is to be understood that the implementations are not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as representative forms of implementing the claims. 

What is claimed is:
 1. A projectile, comprising: a solid metallic cylindrical body with a tapered nose at one end of the body and a blunt or flat base at an opposite end of the body; and an air core disposed through a length of the body from the nose to the base, the air core centered on a central primary longitudinal axis of the body.
 2. The projectile of claim 1, further comprising a relief or depression disposed on an outer surface of the body, around at least a portion of the perimeter of the cylindrical body between the nose and the base, the relief or depression resulting in a diameter of the body being reduced at the relief or depression.
 3. The projectile of claim 1, further comprising a taper around at least a portion of the body where the body meets the base, the taper resulting in a diameter of the base being less than a diameter of a largest portion of the body.
 4. The projectile of claim 1, wherein the cylindrical body is comprised of solid copper or a copper alloy.
 5. The projectile of claim 1, wherein the nose has a generally rounded shape or ogival shape.
 6. The projectile of claim 1, wherein the air core comprises an orifice that extends the entire length of the projectile.
 7. The projectile of claim 1, wherein the air core has a circular or polygonal cross-section.
 8. The projectile of claim 1, wherein a cross-section of the air core is not consistent from the nose to the base.
 9. The projectile of claim 8, wherein a diameter of the air core is greater at one of the nose or the base than the other of the nose or the base.
 10. The projectile of claim 9, wherein the air core has a conical frustrum shape.
 11. The projectile of claim 8, wherein a diameter of the air core is greater at the nose and the base than a point between the nose and the base.
 12. The projectile of claim 11, wherein the air core has a venturi shape.
 13. A projectile, comprising: a solid metallic cylindrical body with a tapered nose at a first end of the body; and an air core comprising an orifice that extends an entire length of the projectile, the air core centered on a longitudinal axis of symmetry of the cylindrical body.
 14. The projectile of claim 13, further comprising a blunt or flat base at an opposite end of the body from the nose.
 15. The projectile of claim 13, further comprising one or more aerodynamics-enhancing features on a surface of the cylindrical body, including one or more tapers, recesses, or depressions in the surface of the cylindrical body.
 16. The projectile of claim 13, wherein a shape of the air core includes one or more aerodynamics-enhancing features, including a diameter that changes size over at least a portion of the length of the projectile.
 17. The projectile of claim 13, wherein the air core is configured to pass air through the air core when the projectile travels through air.
 18. The projectile of claim 13, wherein the air core is configured to collect a quantity of a material within the air core when the projectile penetrates and travels into the material.
 19. The projectile of claim 18, wherein the projectile is configured to tumble or wobble when the quantity of the material is within the air core of the projectile, and wherein the tumbling or wobbling comprises yawing and tilting of the projectile.
 20. The projectile of claim 19, wherein the projectile is configured to form an oversized cavity within the material based on the tumbling or wobbling of the projectile while the projectile travels through the material, the oversized cavity comprising a cavity having a diameter greater than a largest diameter of the cylindrical body. 